Villasante Juliana, Martin-Lujano Anna, Almajano María Pilar
Chemical Engineering Department, Universitat Politècnica de Catalunya, Av.Diagonal 647, 08028 Barcelona, Spain.
Polymers (Basel). 2020 Jun 26;12(6):1424. doi: 10.3390/polym12061424.
Phenolic compounds that come from natural products are a good option for minimizing lipid oxidation. It should be noted that these are not only introduced directly into the food, but also incorporated into edible biofilms. In contact with food, they extend its useful life by avoiding contact with other surface and preventing deterioration air, one of the main objectives. In particular, gelatin is a biopolymer that has a great potential due to its abundance, low cost and good film-forming capacity. The aim of this study has been to design and analyse gelatin films that incorporate bioactive compounds that come from the walnut and a by-product, the walnut shell. The results showed that mechanical and water vapor barrier properties of the developed films varied depending on the concentration of the walnut, shell and synthetic antioxidant. With increasing walnut concentration (15%) the permeability to water vapor (0.414 g·mm/m·day·Pascal, g·mm/m·day·Pa) was significantly lower than the control (5.0368 g·mm/m·day·Pa). Furthermore, in the new films the elongation at the break and Young's modulus decrease by six times with respect to the control. Films with pure gelatin cannot act as an antioxidant shield to prevent food oxidation, but adding pecan walnut (15% concentration) presents 30% inhibition of the DPPH stable radical. Furthermore, in the DSC, the addition of walnut (15 and 9% concentrations), showed the formation of big crystals; which could improve the thermal stability of gelatin films. The use of new gelatin films has shown good protection against the oxidation of beef patties, increasing the useful lifetime up to nine days, compared to the control (3-4 days), which opens up a big field to the commercialization of meat products with lower quantities of synthetic products.
来自天然产物的酚类化合物是最大限度减少脂质氧化的良好选择。应当指出的是，这些化合物不仅可以直接添加到食品中，还可以掺入可食用生物膜中。与食品接触时，它们通过避免与其他表面接触并防止空气（主要因素之一）导致的变质来延长食品的保质期。特别是，明胶是一种生物聚合物，因其丰富性、低成本和良好的成膜能力而具有巨大潜力。本研究的目的是设计和分析含有来自核桃及其副产品核桃壳的生物活性化合物的明胶膜。结果表明，所制备薄膜的机械性能和水蒸气阻隔性能因核桃、核桃壳和合成抗氧化剂的浓度而异。随着核桃浓度（15%）的增加，水蒸气渗透率（0.414 g·mm/m·天·帕斯卡，g·mm/m·天·Pa）显著低于对照组（5.0368 g·mm/m·天·Pa）。此外，新薄膜的断裂伸长率和杨氏模量相对于对照组降低了六倍。纯明胶薄膜不能作为抗氧化屏障来防止食品氧化，但添加山核桃（浓度15%）对DPPH稳定自由基有30%的抑制作用。此外，在差示扫描量热法（DSC）中，添加核桃（浓度15%和9%）显示形成了大晶体；这可以提高明胶膜的热稳定性。新型明胶膜已显示出对牛肉饼氧化有良好的保护作用，与对照组（3 - 4天）相比，保质期延长至九天，这为减少合成产品用量的肉类产品商业化开辟了广阔前景。
